This invention relates to container cappers and, more particularly, to container cappers which utilize improved container cap grasping and rotating mechanisms and improved torque sensing and controlling devices therein. It also relates to container cap torque testers and improved apparatus for testing for and uncapping improperly capped containers.
Container cappers and torque testers are commonly used in commercial container filling lines wherein glass or plastic containers are filled with liquids or powders and then capped. The cappers are positioned downstream of the container filling apparatus and sequentially receive filled containers from that apparatus via a conveyor belt, guide ramp or the like. The cappers also sequentially receive oriented container caps from an upstream cap unscrambling device via a second conveyor belt, guide ramp or the like.
Conventionally, the capper clamps the filled containers that sequentially arrive at its work station. It also grasps individual ones of the caps that are delivered to it, places the grasped cap on the clamped container and rotates the cap to secure the cap onto the container. Then, with the container capped, the cap grasper and container clamps are released and the container is allowed to be moved away from the capper by a suitable conveying means, for example the belt which brought it to the capper.
Although the foregoing method for capping containers is quite satisfactory, the cappers that have been used in connection with this method have been a trouble spot in the container filling lines for a number of reasons, including the following. The mechanism for tightening caps onto containers has, due to a lack of adjustability in or difficulty in making adjustments to the amount of torque exerted during the cap-tightening process, resulted in leaky containers, requiring time consuming and expensive reworking and testing of contemporaneously made containers. Also, the mechanism for grasping caps has frequently damaged the caps, due to the use of excessive and/or non-uniform grasping forces therein, causing containers to have to be rejected and causing slowdowns in the filling lines. Similarly, prior cappers have generally been so arranged that when grasper jaw changes have had to be made, either due to changes in the sizes of the caps and containers that were being processed or due to damage to the jaws in use, extensive delays were encountered while the capper was disassembled sufficiently to allow the jaws to be replaced.
It is, therefore, a primary object of this invention to provide improved container cappers and torque testers.
Another object of this invention is to provide cappers and torque testers having improved mechanisms therein for adjusting the amount of torque used in tightening caps on containers.
A further object of this invention is to provide cappers and torque testers having improved cap grasping mechanisms therein.
Another object of this invention is to provide a capper in which minimum grasping pressure is uniformly applied to the jaws to center, pick up and place the cap on the container, and in which the grasping pressure increases proportionately with torque resistance to prevent slippage of the jaws relative to the caps.
Yet another object of this invention is to provide cappers and torque testers wherein the cap grasper jaws are replaceable without requiring major disassembling of the cappers and torque testers.
A still further object of the invention is to provide a capper in which torque sensing is employed to stop rotation of the capper head and to open the cap grasper jaws at the end of the capping operation.
Further objects and advantages of this invention will become apparent as the following description proceeds.